1. Field of the Invention
The present invention relates to a method for incorporating dye and/or nanoparticles into polymer films and into electrospun polymeric nanofibers, and, more specifically, to a method for electrospinning a molecularly homogenous solution of dye (and/or nanoparticles) and polymer dissolved in a mutual solvent leading to uniform distribution of dye across the cross-section of each constituent fiber and to resulting nanofibers with the dye incorporated therein.
2. Description of the Related Art
The world market for neonatal and pediatric internal feeding devices in 2013 is $2.06 billion and is estimated to grow at the rate of 4.9% and reach $2.62 billion by 2018. The nasogastric (NG) tube market is generating the second largest revenue after enteral feeding pumps, accounting for 14% and 59% of the overall market respectively. Proper placement of NG tubes is critical to avoid perforation injuries and instillation of nutrient solution into lungs or body cavities. Currently radio-opaque markings are visualized radiologically to verify placement, as well as color pH sensors and ultrasound. A need exists for improved non-invasive real time imaging of pediatric NG tubes that avoids the use of ionizing radiation.
Electrospinning is a technique that is used for fabrication of nanofibers from thermoplastic, solvent-soluble polymers. Near Infrared (NIR) dyes function by absorbing light in the near IR portion of the optical spectrum and emitting light (in response to this) at a different wavelength also in the near IR portion of the optical spectrum. Near IR light is particularly interesting for medical applications, as mammalian tissue is particularly transmissive in this portion of the optical spectrum (just put a lamp behind your hand and you can see red light transmitted), indicating that it may be useful surgically.
Shape memory (SM) polymers are polymeric networks that feature a permanent, stress-free state and a multitude of temporary shapes fixed by mechanical manipulation in a rubbery state (above Tm or Tg, termed “triggering temperature”), followed by cooling. An environmental stimulus can be applied to trigger a shape transition from temporary to permanent shape. Highly entangled polymers can feature a shape memory, entanglements serving as physical crosslinks if their lifetime is longer than the deformation time. Currently, a method of incorporating a dye into polymer films and into electrospun polymeric nanofibers is accomplished by diffusion from an immersion solution.